#include <stdio.h>
#include <string.h>


int main()
{
    char buffer[] = "hello world";
    int length = strlen(buffer);
    
    for(int idx = 0;idx < (length/2);idx++)
    {
        char temp = buffer[idx];
        buffer[idx] = buffer[length-1-idx];
        buffer[length-1-idx] = temp;
    }

    printf("buffer[] = %s\n",buffer);

    return 0;
}